Highway Performance Monitoring System (HPMS)

HPMS Reassessment 2010+

Final Report

Prepared by:

Office of Highway Policy Information
Federal Highway Administration

2.0 Background

2.1 Highway Performance Monitoring System (HPMS)

2.1.1 History of HPMS

The HPMS was developed in 1978 as a national highway transportation system
database. In its current configuration, it includes limited data on all public
roads, more detailed data for a sample of the arterial and collector functional
systems, and area-wide summary information for urbanized, small urban, and
rural areas. The HPMS replaced numerous uncoordinated annual state data reports
as well as biennial special studies conducted by each state. These special
studies had been conducted to support a 1965 Congressional requirement that
a report on the Nation’s highway needs be submitted to Congress every
two years. The first such Conditions and Performance Report was
compiled in 1968. The first report to make use of the HPMS database was the
1980 Conditions and Performance Report, which was forwarded to Congress in
January 1981.

Providing a snapshot of highway conditions was another reason for the original
development of HPMS. In the 1970s, FHWA discovered that it had to respond
to Congressional inquiries about the status of the Nation’s highways.
HPMS provides a way to measure and track trends in highway characteristics,
pavement conditions, and congestion at a national level.

The major purpose of the HPMS is to provide data that reflects the extent,
condition, performance, use, and operating characteristics of the Nation’s
highways. To meet this primary objective, the HPMS has gone through an evolutionary
process that has recognized over time the changing needs for data related
to these purposes.

2.1.2 Mission and Goals of HPMS

It is the mission of the Highway Performance Monitoring System (HPMS), as
an integral part of the Nation’s suite of transportation databases,
to provide a database and analysis process for assessing and reporting the
extent, condition and performance of the Nation’s highway system in
the most cost-effective manner consistent with the following goals:

Meet FHWA’s highway stewardship responsibilities, including preserving
the national interest in the NHS;

Provide a database, analytical tools, and FHWA technical support that
meets the needs of state, regional, and local agencies; and

Evolve to a data system which:

— Builds from the data systems of local, regional, and state
governments;

— Is connected with a common geo-referencing system; and

— Avoids, whenever possible, collecting data which is not used
by the collecting agency.

Appendix A contains a list of commonly used acronyms and abbreviations.

2.1.3 HPMS Description

The HPMS is a key national transportation data program that provides national-level
highway inventory, condition, performance, and operating characteristics
data to national, state, and regional customers. Examples of the type of
data available through HPMS include pavement condition and travel by vehicle
type.

There are three primary functions involved with HPMS: data collection, processing/reporting,
and analyzing/applying. Although there is some overlap among functions, each
function is primarily conducted by a different stakeholder group. Data collectors
are state departments of transportation, metropolitan planning organizations,
and local governments such as counties and cities. The processing and reporting
of HPMS occurs within the FHWA Office of Highway Policy Information. Finally,
users consist of a wide variety of customers, including U.S. DOT Federal
Program Offices, other Federal agencies, U.S. Congress, states, MPOs, counties,
and cities.

HPMS is used at the federal level for apportionment, performance measures,
highway statistics and conditions reporting, and analytical models; it is
one of the primary databases used by FHWA for conducting national-level surface
transportation planning and policy studies. It is also used by a variety
of state and local transportation agencies as well as other transportation
interests. Some of these uses are extremely important for highway financing.
For example, the biennial Conditions and Performance Report (C&P) to
Congress documents future highway funding needs and HPMS-derived vehicle-miles
traveled (VMT) estimates are used in the annual apportionment of Federal
Aid highway funds to the states.

VMT estimation is probably the most ubiquitous use of HPMS — VMT is
calculated and used at the national, state, and local levels. This is not
surprising since the original primary intent of HPMS, when it was conceived
in the late 1970s, was to provide a consistent basis for VMT estimation nationally.
This is reflected in the sampling frame and the strong linkage to the Traffic
Monitoring Guide for supplying traffic counts to HPMS.

The data also are used for assessing highway system performance under FHWA’s
strategic planning process. Pavement condition data, congestion-related data,
and traffic data are used extensively by the Administration to measure FHWA’s
and the State’s progress in meeting the objectives embodied in the
Vital Few, FHWA’s Performance Plan, and other strategic goals.

Over time, many applications have been developed that use HPMS as their
source of data. These applications further demonstrate the utility of HPMS
and have also put increasing demands on it. For example, the HERS model has
become FHWA’s tool for developing the highly visible C&P Report and
the Freight Analysis Framework (FAF) is used extensively for estimating current
and future freight movement at the national-level such as in the Freight
Facts and Figures series.

In addition, the HPMS serves needs of the states, MPOs and local government,
and other customers in assessing highway condition, performance, air quality
trends, and future investment requirements. Some states rely on traffic and
travel data from the HPMS to conduct air quality analyses and make assessments
related to determining air quality conformity. Others are using the same
analysis models used by FHWA to assess their own highway investment needs
using HERS—ST, which is the state version of the HERS model used by
FHWA. As a result of these uses, states have an additional stake in assuring
the completeness and quality of these data.

Finally, these data are the source of a large portion of information included
in FHWA’s annual Highway Statistics and other media and publications.
They are widely used in both the national and international arenas by other
governments, transportation professionals, and industry professionals to
make decisions that impact national and local transportation systems and
our transportation dependent economy.

HPMS is used by many transportation professionals to produce various
reports, including AASHTO’s “Bottom-line” reports,
the Transportation Research Board’s policy studies, and the American
Highway Users Alliance bottleneck studies.

The FHWA OHPI is not involved directly in data collection but relies on
State DOTs for HPMS Data. OHPI performs data quality checks, and provides
technical support and software to ease reporting requirements. The fact that
FHWA relies on other agencies to provide data is highly significant since
FHWA must balance the needs of its users (internal and external) with the
capabilities of its providers to provide data at a reasonable level of effort.
The difference in views between data needs and collection capabilities is
the crux of the issue addressed during the Reassessment. A large number of
data issues were considered and explored, and the organization and prioritization
of the issues from a user and provider standpoint are key elements of the
Reassessment.

There is generally a lag between data collection in the field and the data
showing up in a report. The following table indicates the timing of data
collection and reporting.

Table 2.1.3 HPMS Timeline

2.2 Reassessment

2.2.1 Background of HPMS Reassessments

The HPMS has been modified several times since its inception. Changes in
coverage and detail have been made since 1978 to reflect changes in highway
systems; legislation and national priorities; to reflect new technology;
and to consolidate or streamline reporting requirements.

Recognizing that needs and capabilities change over time, FHWA initiated
a periodic review process for HPMS many years ago (“Reassessment”).
The Reassessment process considers what changes should be made to HPMS data
elements and collection procedures, including:

Should existing data elements be eliminated because they are not needed
for most applications or because they are too onerous a burden on data
collectors?

Are new data elements needed to support current and emerging applications?
If so, can they be prioritized or limited to certain functional systems?

Should data be collected in a different manner (e.g., the factoring
and reporting of traffic counts)?

What changes in the sampling schema should be made? Are the minimum
VMT-based sample sizes adequate for providing system-level estimates of
other highway conditions?

The last Reassessment was completed in 1999 and utilized a comprehensive
stakeholder outreach process. In 1999, there was some question as to the
need for HPMS, whereas this Reassessment is being performed in an environment
where HPMS is recognized as an important program that needs some modifications
to accommodate changing technological and application needs.

2.2.2 Purpose of this Reassessment

The purpose of this Reassessment is to review the HPMS in
light of contemporary issues and anticipated future needs. The reauthorization
of the Federal-aid highway program, as contained in SAFETEA—LU, provided
an appropriate opportunity for the FHWA to undertake a Reassessment of the HPMS.
Other reasons to reexamine the HPMS are further advancements in technology,
changes to state data requirements, increased use of performance measures,
and changes in the various uses of HPMS data by government, academia, and
the private sector.

The vision for this Reassessment is for HPMS to meet the transportation
community’s data needs in 2010 and beyond.

The mission is to respond to current and future business needs, address
new data needs in SAFETEA—LU, capitalize on changing technology and,
where possible, address resource constraints and institutional changes.

The objectives are to:

Meet new Federal needs including but not limited to: Policy, Safety,
Operations, and Infrastructure;

Explore potential changes to HPMS to be more useful for most states
and MPOs;

Capitalize on changing technology to enhance quality, efficiency, and
data integration; and

The process for this Reassessment was carefully planned and implemented
to ensure consistency with the process used for the last Reassessment. It
also was designed to address policy/institutional (state and national) issues,
data collection, data analysis tools/applications, emerging issues (such
as safety), and all other issues related to HPMS users and collectors.

The first phase of the Reassessment was to identify what needed to be changed
in coordination with Federal agencies. The second phase was to work with
stakeholders to identify how the needs can be met and balanced with collection
requirements. The third phase is the implementation of the identified needs
within the context of the new data model.

2.2.3 How HPMS Addresses National Transportation Data Needs

The Federal need for transportation data transcends functional classification,
ownership, and jurisdiction. While functional class, ownership, and jurisdiction
are important categories, for which HPMS data are often summarized, they
do not define the limits of FHWA’s needs for these data. Each issue
area explored in this reassessment has had to consider the differing Federal
and state data needs, while weighing these needs against the states’ ability
(or willingness) to provide these data.

The ability to provide data, especially on roads not owned by the states
(off-system), was often cited as being an area of concern. This was neither
a surprise nor a new topic in the Reassessment; this has been a concern of
the states since the inception of HPMS in 1978. However, to get a complete
picture of the highway system in each state it has always been necessary
for FHWA to have data on off-system roads.

The existing HPMS structure attempts to balance the need for off-system
data with the States ability to provide these data, by dividing the HPMS
data into three levels. Sample data are the most detailed, with each sample
section being comprised of up to 98 data items. In the 2006 HPMS data, there
are approximately 120,000 sample sections, with a total length of 137,000
miles. These sections represent approximately 980,000 miles of roads functionally
classified from Interstate through (Major) Collector.

The next level is the universe data. Universe sections can contain a maximum
of 46 data items on NHS sections, to a minimum of 28 data items on local
roads. It should be noted that currently, most of the data on local roads
are identification, system, jurisdictional, or ITS in nature. The “section
length” data item is the only apportionment item (from these data)
for local roads. Nationwide, there are approximately 1.13 million universe
sections that represent all 4.012 million miles of public roads (2006 HPMS).

The final HPMS data level is the summary data. These data provide travel
data for all functional systems, as well as the distribution of travel by
six vehicle classes for all functional systems. Additional summary data are
collected by urban/urbanized area, and for air quality non-attainment and
maintenance areas.

These data are used individually or in combination to satisfy the various
Federal data needs. The apportionment of Highway Trust Funds relies on all
three data levels. Performance measures can use either the sample data alone
or in combination with the universe data. Much of the HERS analysis for the
C&P Report utilizes just sample data.

Key to the multilevel structure of HPMS is the national uses of these data;
the quality of data; and the types of analyses performed using these data.
The multilevel approach also helps compensate for variability between state
transportation data collection efforts. States typically focus their data
collection efforts on roads owned and maintained by the state. The following
is from the 2006 HPMS data and illustrates the variability in state owned
highway systems nationwide:

The degree of state ownership ranges from a low of 6.0 percent of the
mileage carrying 41.8 percent of the VMT to a high of 92.8 percent of mileage
carrying 93.4 percent of VMT. The national averages are 19.4 percent of
mileage and 64.2 percent of VMT.

State ownership by Federal-aid highways is 90.4 percent for Interstate,
95 percent for other NHS and 49.3 percent for other Federal-aid highways.

While states generally have responsibility for higher functionally classified
highways, 159,574 miles of state highways are functionally classified as
Local highways and 80,999 miles are urban Collectors and rural Minor Collectors.

It is important to note that increasingly states are relying on other governmental
agencies to provide HPMS data on off-state system roads. Cities, counties,
and MPOs frequently provide HPMS data to the states, which then combine it
with state-collected data before submitting it to FHWA. Ideally, FHWA would
like all data to be of equally high quality, but it realizes that this is
not always possible across all functional systems. FHWA continues to support
the utilization of locally collected data in states’ HPMS submittals.

States generally follow the guidance and criteria, such as for functional
class, but each state is different because of internal state and non-state
highway organizations, highway system definitions, and operating procedures
and regulations. To better accommodate these differences, FHWA is proposing
several improvements to HPMS that will increase the ability of states to
more efficiently provide quality, timely, and complete HPMS data. These improvements
discussed in this report include:

New data model;

Metadata for pavements and traffic;

Coordination with safety, bridge, finance, and other databases;

Boundaries and functional classification.

Sample size and national/state system sampling schema are two areas that
could be improved to address this issue, but due to budget and time limitations
are being retained as long-term research projects for implementation in the
mid to long term; beyond year 2010.

2.3 Uses of HPMS Data

2.3.1 Needs Assessment

The methods and assumptions used to analyze future highway, bridge, and
transit investment scenarios are continuously evolving. Since the beginning
of the highway report series in 1968, innovations in analytical methods,
new empirical evidence, and changes in transportation planning objectives
have combined to encourage the development and application of improved data
and analytical techniques. Estimates of future highway investment requirements,
as reported in the 1968 National Highway Needs Report to Congress,
began as a combined “wish list” of State highway “needs.” As
the focus of national highway investment changed from system expansion to
management of the existing system during the 1970s, national engineering
standards were defined and applied to identify system deficiencies, and the
investments necessary to remedy these deficiencies were estimated. By the
end of the decade, a comprehensive database, the Highway Performance Monitoring
System (HPMS), had been developed to monitor highway system conditions and
performance nationwide.
By the early 1980s, a sophisticated simulation model, the HPMS Analytical
Process (AP), was available to evaluate the impact of alternative investment
strategies on system conditions and performance. The procedures used in the
HPMS-AP were founded on engineering principles. Engineering standards were
applied to determine which system attributes were considered deficient, and
improvement option “packages” were developed using standard engineering
practice to potentially correct given deficiencies, but without consideration
of comparative economic benefits and costs.

In 1988, the FHWA embarked on a long-term research and development effort
to produce an alternative simulation procedure combining engineering principles
with economic analysis, culminating with the development of the HERS model.
HERS was first utilized to develop one of the two highway investment scenarios
presented in the 1995 C&P report. In subsequent reports, HERS has been
used to develop all of the highway investment scenarios.

The HERS model initiates the investment analysis by evaluating the current
state of the highway system using information on pavements, geometry, traffic
volumes, vehicle mix, and other characteristics from the Highway Performance
Monitoring System (HPMS) sample dataset. Using section-specific traffic growth
projections, HERS forecasts future conditions and performance across several
funding periods. As used in this report, the future analysis covers four
consecutive 5-year periods. At the end of each period, the model checks for
deficiencies in eight highway section characteristics: pavement condition,
surface type, volume/service flow (V/SF) ratio, lane width, right shoulder
width, shoulder type, horizontal alignment (curves), and vertical alignment
(grades).

Once HERS determines a section's pavement or capacity is deficient, it will
identify potential improvements to correct some or all of the section's deficient
characteristics. The HERS model evaluates seven kinds of improvements: resurfacing,
resurfacing with shoulder improvements, resurfacing with widened lanes (aka
minor widening), resurfacing with added lanes (aka major widening), reconstruction,
reconstruction with widened lanes, and reconstruction with added lanes. For
improvements that add travel lanes, HERS further distinguishes between those
that can be made at “normal cost” and those on sections with
limited widening feasibility that could only be made at “high cost.” HERS
may also evaluate alignment improvements to improve curves, grades, or both.

When evaluating which potential improvement, if any, should be implemented
on a particular highway section, HERS employs incremental benefit-cost analysis.
The HERS model defines benefits as reductions in direct highway user costs,
agency costs, and societal costs. Highway user benefits are defined as reductions
in travel time costs, crash costs, and vehicle operating costs. Agency benefits
include reduced maintenance costs (plus the residual value of projects with
longer expected service lives than the alternative). Societal benefits include
reduced vehicle emissions. Increases in any of these costs resulting from
a highway improvement (such as higher emissions rates at high speeds or the
increased delay associated with a work zone) would be factored into the analysis
as a “disbenefit.”

These benefits are divided by the costs of implementing the improvement
to arrive at a benefit-cost ratio (BCR) that is used to rank potential projects
on different sections. The HERS model implements improvements with the highest
BCR first. Thus, as each additional project is implemented, the marginal
BCR and the average BCR of all projects implemented decline. However, until
the point where the marginal BCR falls below 1.0 (i.e., costs exceed benefits),
total net benefits will continue to increase as additional projects are implemented.
Investment beyond this point would not be economically justified, since it
would result in a decline in total net benefits.

Additional information on the HERS model can be found in the HERS Technical
Report. The latest published version dated December 2000, is based
on HERS version 3.26, which was utilized in the development of the 1999
edition of the C&P Report. The Technical Report for
the State version of HERS was published in 2002 and can be found at: http://isddc.dot.gov/OLPFiles/FHWA/010945.pdf.

2.3.2 Performance Measures

HPMS data are used for a number of performance measures in FHWA, the National
Highway Transportation Safety Administration (NHTSA), and the Federal Motor
Carrier Safety Administration (FMCSA). For most of the performance measures,
HPMS data are combined with other data, but there are some that rely solely
upon HPMS. While data on the use and extent of the nation’s highway
system are commonly cited in FHWA documents and in the media, they are not
typically considered performance measures. The term refers to measures or
goals established by the U.S. Department of Transportation or one of the
individual agencies such as FHWA or NHTSA. The following is a brief description
of some of the more commonly referenced performance measures and the HPMS
data used.

2.3.2.1 Fatality Rates — Safety

The FHWA Office of Safety and NHTSA use VMT data derived from HPMS as the
denominator in calculating fatality rates. This is done by dividing the total
number of fatalities by the total VMT. VMT is determined for each section
in HPMS by multiplying the AADT by the length of the section. The VMT are
then summed for the various systems for which a fatality rate is desired;
typically by State, functional class, and vehicle type. HPMS universe, sample,
and summary data are all utilized for this analysis.

2.3.2.2 Pavement Smoothness — Mobility and Productivity

The FHWA Office of Pavement Technology reports the pavement smoothness performance
measure, which is the percent of VMT on the NHS with pavement smoothness
(IRI) of 95 inches/mile or better. HPMS universe data are used for this analysis,
which involves determining 1) which sections on the NHS have an IRI of 95
in/mi or better, 2) calculating the VMT for each section, and 3) summing
of VMT for these sections.

2.3.2.3 Congestion — Mobility and Productivity

The Office of Operations is responsible for the congestion performance measure,
which is the percent of travel that occurs under congested conditions and
is determined by the Texas Transportation Institute (TTI) and reported in
their annual Urban Mobility Report. TTI uses HPMS sample data for approximately
403 urbanized areas within the United States on the freeways and arterial
streets. Addition information on the Urban Mobility Report can be found on
the TTI web site at: http://mobility.tamu.edu.

2.3.2.4 Special Analyses

HPMS data are routinely used for special analysis of highway system extent,
condition, performance, and use. Some of these are recurring such as the
analysis done for the Highway Cost Allocation Study or the Freight Analysis
Framework. Of the non-recurring, some are very complex, but most are rather
simple. The Strategic Multimodal Analysis (SMA) is an example of more complex
analysis to use HPMS sample data, which builds off of the HERS analysis.
Most, however, are along the lines of estimating the extent of access controlled
Principal Arterials, or summing highway mileage by special traffic volume
or pavement condition groups. The FAF uses HPMS passenger traffic data in
assembling the freight corridors and determining freight movement performance.

2.3.2.5 Reports

HPMS data are cited in numerous DOT and FHWA publications. Some, such as Highway
Statistics and the Conditions and Performance Report, which
are produced by the Office of Policy and Governmental Affairs, have entire
chapters dealing with HPMS data. The Bureau of Transportation Statistic’s Pocket
Guide to Transportation is an example of a DOT report that summarized
some of the HPMS data for multiple years. Most reports cite key statistics,
such as the miles, lane-miles, or VMT for all public roads, or a portion
as in the case of the Interstate System or National Highway System.